Check engine light: vacuum leak
04-11-10, 09:52 AM
#32
Driver School Candidate
So, I too am going through this situation. PO171 code with my recently purchased 2000 RX300 with only 67,000 miles on it. I've cleaned the MAF twice this latest time with a q-tip. I reset the CEL and everything is good, but then after a week of driving the light came on again with 171. Power seems to be fine, then again I don't know since I just bought the car a few months ago. Not losing mileage either. My next step is to check for vacuum leaks. Also have an aftermarket MAF sensor coming. Fingers crossed...
04-25-10, 06:28 PM
#34
Driver School Candidate
Man, installed the new MAF sensor and the Check Engine light came back on again after about 100 miles of driving, then it went off again without resetting then this afternoon the error came back again. Is there a DIY vacuum test post somewhere? I just need to know where the vacuum is located so I can spray some brake cleaner. Thanks.
04-26-10, 07:26 AM
#35
Moderator
Is the brake cleaner safe to be introduced in the vacuum line?
Salim
Salim
04-26-10, 06:54 PM
#37
Driver School Candidate
04-26-10, 06:58 PM
#38
Driver School Candidate
Going to replace the air filter with an OEM one. I noticed the light after my wife went to Walmart for an oil change. She mentioned they changed the air filter. If that doesn't work I'll change the gas cap.
BTW, the light seems to come on when I am accelerating on the freeway.
Oh, I checked the often mentioned hose that's behind the MAF and it's connected.
BTW, the light seems to come on when I am accelerating on the freeway.
Oh, I checked the often mentioned hose that's behind the MAF and it's connected.
04-26-10, 08:38 PM
#39
Moderator
Salim
04-26-10, 08:39 PM
#40
Moderator
Going to replace the air filter with an OEM one. I noticed the light after my wife went to Walmart for an oil change. She mentioned they changed the air filter. If that doesn't work I'll change the gas cap.
BTW, the light seems to come on when I am accelerating on the freeway.
Oh, I checked the often mentioned hose that's behind the MAF and it's connected.
BTW, the light seems to come on when I am accelerating on the freeway.
Oh, I checked the often mentioned hose that's behind the MAF and it's connected.
Salim
04-27-10, 07:51 AM
#41
Driver School Candidate
04-27-10, 08:48 AM
#42
Driver
Join Date: Sep 2009
Location: Michigan
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Just a note, my air box is not tightly sealed, only used zip ties. The oil change dude lost two clips for the air box, so I had to improvise. Can't just buy the clips, have to buy the entire air box assembly for several hundred dollars. CEL and VSC light would come on occasionally with air box intact, seems to come on less now with zipped tied, leaky air box. So air filter and air box is not a fix. I have had best results with just re tightening the gas cap. Car runs no different with lighs on or off.
04-27-10, 09:20 AM
#43
Moderator
If the end objective is the car that runs, you are OK. But the electronics in the car are observing an out of range value from a sensor or two and making its best effort to compensate for it and throwing out a code. In the county I live in, we are required to pass an emission test and typically you fail with CEL on. And parts, labor (DIY --> my time) will not get any cheaper over time, so I would do all I could to solve the problem. Or keep at it.
Vacuum leaks are hard to trace. A fiend of mine had a leak in a bellow-like hose. At idle there would be no leak and when you gas the engine, it would torque of the mounts and open up the bellow to let in air. Try the carb-cleaner.
Salim
Vacuum leaks are hard to trace. A fiend of mine had a leak in a bellow-like hose. At idle there would be no leak and when you gas the engine, it would torque of the mounts and open up the bellow to let in air. Try the carb-cleaner.
Salim
09-11-10, 01:49 PM
#44
Driver School Candidate
Join Date: Jan 2008
Location: Florida
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I just had a code 0442 and read the posts, checked the little hose, seemed half way on, took off the neg. on the battery, put it back on and the code is gone....I have driven it around the neighborhood and turned it on and off a few times stopping in on other neighbors...I wonder if it is fixed? I will post the outcome.....
Wife called while out and said the check engine light is back on...
Hmmm,
the code definition says gas cap , so I replaced it.....shall see if that code rears it'ds ugly head again.
Wife called while out and said the check engine light is back on...
Hmmm,
the code definition says gas cap , so I replaced it.....shall see if that code rears it'ds ugly head again.
Last edited by Sc5Speed; 09-19-10 at 06:34 AM.
10-18-10, 04:38 PM
#45
The hose lexmex is referring to is part of the evap system and when disconnected will through off P0440, P441 and P0446 codes. This is a common problem as it is very easy to disconnect the hose when lifting up the top of the air box to check the air filter. The hose is located behind the air box and connected to the top/back of the lid. It is directly under the brake fluid resovoir. The hose connects to a metal tube about 10" down. This is where it usually disconnects.